Contains spoilers for this episode and earlier episodes.
Seo-jun and Su-ho's cafeteria confrontation becomes a fight, and the school calls them in for discipline. Flashbacks connect their hostility to Se-yeon, who died after a public scandal and had trusted Su-ho to believe him. Their classmates interpret the fight as a contest over Ju-kyung, leaving her to deny that she is dating either boy. At Prince Comics, Su-ho remembers the girl who once cheered him up there as a child. Ju-kyung calls him her guardian angel because he is protecting her secret, while their shared reading brings them closer away from the school's gossip.
Soo-ah arranges a blind date for Ju-kyung, and Su-ho leaves his mathematics competition to follow her to the cinema. He interrupts the wrong couple before discovering that her actual date already has a girlfriend. After Su-ho confronts him, the boy sends Ju-kyung a message admitting it. Elsewhere, the friendship between Ju-kyung and Seo-jun's mothers creates an awkward meeting at the salon, where she hides behind a face mask. She photographs his motorcycle to counter the embarrassing pictures he takes of her. A later encounter with men chasing Seo-jun sends them running together, and both boys help carry Hee-kyung home when she is drunk. Seo-jun learns that Su-ho likes Ju-kyung and begins openly pursuing her attention.